Excavating machine



June 23, 1925. 1,543,250

R. R. DOWNIE EXCAVATING MACHINE Filed Jan. 8. 1925 3 Sheets-Sheet l INVENTOR WITNESSES ATTORNEY To all whom it may concern:

Patented June 23, .1925.

UNITED STATES PATENT? OFFICE.

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nxcavame Application filed January a, 1925. Serial 10. 1,878.

Be it known that I, Roam Dowmn,

.a citizen of the United States, residing at Beaver Falls, in thecountyv of Beaver and State of Pennsylvania, have invented a new and useful Excavating Machine, of whic the following is a specification.

This invention relates to excavating ma- I. chines, and particularly to those of the drag stick, ditcher type, such as that disclosed in U. S. Patent No. 1,511,114, granted to me October 7, 1924, and it consists primarily in an improved device for controlling the position of the ditcher scoop.

The object of the present invention is to provide an improved construction, which will positioning or spotting of the loaded scoop when elevated as for dumping, and to permit greater positiveness and accuracy'in controlling the position of the scoop within that range than is otherwise feasible.

To the attainment of the foregoing, the

invention comprises means for temporarily modifying the action of the system of pive oted parts about the outer end of the boom during the dumping phase of the cycle of operation. More specifically, it consists in the provision of means for suspending the action of the connecting bar pivot, so that the connecting bar and the ditcher stick remain relatively motionless during such interval as the boom remains above a predetermined angle of elevation. In the specific embodiment of the invention, which is herein described and illustrated, this means consists in the provision of suitable stops on the connecting bars and ditcher stickadapted to contact with each other when these on the side opposite to the 'ivot bolt 7 and somewhat above the same, a caring 12 is separts have reached their predetermined angle of relative approach.

The specific construction of the invention,

- accompanying drawings illustrating the inventionin its preferred form.

In the accompanying drawings: 7 7 Figure 1 is a side elevation of amachine embodying "the inventionand showing the boom raised. Figure 2'is a similar view on an enlarged ermit a much greater latitude in the tion in connection with the boom, ditcher stick and connection bar.

Figure 4 is a plan view of the connecting bar 'and ditcher stick.

Figure 5 is a detail view of the st0p.m' emher secured to the connecting bar.

Figure 6 is a detail view of the connection hetween the ditcher stick and connecting Figure 7 is a detail view of the connection between-the ditcher stick andthe boom.

The invention is shown in connection with an excavating machine 1, having a mast 2, which is connected thereto by a pair of vertically alined pivots 3. The b0 m 4 is pivotally connected at 5 to the ast', and is adapted to be swung upwardly and downwardly. The outer end of the boom has extension irons 6 secured thereto," the outer ends of which are traversed by a pivot bolt 7 for supporting the ditcher stick 8. The ditcher stick is formed from a pair of channel bars, as shown in Figures 3, 4, 6 and 7, and secured to the rear face of the stick is a bearing 9, provided with a cap 10 fOllB- ceiving' .a sleeve 11in which the pivot bolt 7 is secured. The sleeve 11 extends be mad the bearings sufiiciently, so that the ead and nut of the bolt 7 may be secured thereto without binding the extension irons 6 of the boom.

At the upper end of the ditcher stick 8,

comp'risesa pair of spaced strap irons, intermediately connected by a bracket 16, and traversedat their rear ends by a; pin 17 on which a hoistin sheave 18 is mounted. "A

scoop 19 is carried at the lower end of the ditcher stick 8, and base hauling bail 20, which is connected by a hauling cable 21 to a suitable source of power on the machine. A second cable 22 passes over the hoisting sheave 18. The operation of raising and lowering the boom 4, andvthe ditcher stick the pivot bolt 7 will be substantially in the line of pull between the cable 22 and the connecting bar pivot 14, so that it is diflicult to swing the scoop 19 outwardly to gain the desired spotting range. In order to prevent this condition, without altering the relative locations of the pivot bolts 7 and 14, I have formed the bracket 16 with depending stop arms 23, which are adapted to engage cooperating stop arms 24, which are formed on the bearing cap 10 and extend upwardly and rearwardly therefrom, thus providing means for positively and efiectively swinging the scoop outwardly by paying out the cable 21, and drawing in on the cable 22 when the pivot bolt 17 is in what may be termed a dead center position.

Without the provision of the cooperating stop arms or abutments 23 and 24, a scoop has only a very limited spotting range when elevated to the height ordinarily required for dumping, and is not positively or accurately controlled within such range as it does have. The immediate reason for this shortness of range is lack of suflicient outward thrusting force to swing the loaded scoop outwardly beyond its plumb position, or to swing it quickly and positively even out to a plumb position; Tins lack of force is, in turn, due to the fact that at this elevation of the boom, the pivot 7 closely aproaches, and at extreme elevations, actually intersects the line of tension between the pivot 14 and the point toward which the cable 22 is drawn. This will be made clear by regarding the bolt 7 about which the ditcher stick swings, as a crank center, the line between the bolt 7 and the bolt 14 as a crank arm, and the bolt 7 to which the power is ap lied as the crank end. Now, when the bolt or the crank center approaches or intersects the true line of tension extending from the machine to the bolt 14, the crank is nearly or actually on dead center position, and the'force exerted upon it by the hoisting line is in the general direction of the length of the crank, and. not in a direction advantageous for causing rotation; A v

The depending part of the stick 8, with the loaded scoop at its lower end, tends, of course, to hang plumb; that is, in such a position that the center of avity of the stick and scoop combined is irectly underneath the pivot 7; and with the roportional arrangement of the parts most a vantageous in actual excavation, the stick is ofsuch a above described, temporarily inoperative,

and to substitute therefor another 'crank arm of a much more effective length and angle, which may be represented by a line from the pivot 7 to the hoisting sheave pin 17 and which effectively serves to alter the normal position of the stick, throughout such interval as the members 23 and 24 are in abutting relation.

The efi'ect of the abutments 23 and 24, therefore, is to cause the loaded and elevated scoop to hang outwardly when in equilibrium at a desirable distance from the boom, and to seek that remote position quickly when the hauling line 21 is paid out. Spotting is effected by paying out or taking in sufiiciently to bring the scoop to the exact position desired for dumping. actual practice, the construction herein described has been found not only to ive. the desired degree of positiveness of actlon, but to increase the spotting range to about twice the range possible without this improvement, and without any offsetting disadvantages. c

It is believed that the attainment of this increased spotting range by other means, such as by altering the relative'location of the pivots 7 and 14 with respect to each other and to the ditcher stick, is not feasible in this type of machine: it will be either prohibitively wasteful of power, or would sacrifice to a prohibitive degree the outward reach. of the stick when lowered and extended at the beginning of the digging operation. The position of the pivots 7 and 14 is actually goverend by considerations of power, economy, and necessary digging travel or sweep of the scoop and can not, therefore, be altered in order to ain the desired spotting range or outward umping reach.

In excavators of this type, for example, the pivot 14 is located a certain distance above the pivot 7. The purpose of this relative arrangement is to cause the tension of the hoisting line 22 not only to support the stick and attached parts, but also to main- .tain a pull upon the upper end of the stick in the direction of the machine, and, with the boom acting as a stifi link, to cause the stick to swing outwardly nearly into lon itudinal' alinement with the-boom; It is obvlous that this initial reach isdesired, and, in fact, indispensable when starting an excavation down through a level surface. The stick 4 the bail20.

assumes and remains in this position of rest or equilibrium, except as restrained or retracted from it by the hauling line 21, which is attached to the bail 20 on the scoop. Digging is effected by first lowering the boom, stick and scoop in this extended position until the teeth of-the scoop engage the material to be excavated, and then winding in the hauling line. 5

It will be seen that the hauling line and the hoisting line are in some degree actually movements of the scoop, namely, inward,-

outward and upward, with but two cables.

-Also, it will be seen that the measure of this antagonism liesin the relative proportions of two spacings, the distance from the stick pivot 7 to the pivot 14, as compared to the distance from the pivot 7- to the pivot f Now, in order that th'ejleastpossible amount of power may be neutralized in the digging operation,.by reason of the antagonism of the o posed pulls on the cables 21 and 22, the point 14 of the hoisting line attachment is located at the shortest possible distance above the fulcrum or pivot 7 of the ditcher stick; that is, the shortest pos sible distance which will constitute a l everage of suificient length to cause the "stick when in equilibrium to be in the outward position which is necessary for starting the excavation; and the point 'of attachment of the hoistin line is located in such a direction from t e pivot 7, and with such angular relation to the length of the stick as to give-v the greatest possible effect to the powerapplie to the cable 22 forswinging the'lower end of the stick outwardly preparatory to digging. The necessities of eflicient use of,

power and suflicient digging range govern the location of the pivot 14 with reference to the pivot 7, both as to distance and direction, so that it can not be altered in order to'. secure the advantage ofi increased spotting or dumping range, but the latter is secured in a practical manner'by the provision of the abutting members 23' and 24.

While I have'shown and described specifically one form in which the invention may be embodied, it is apparent that the same may be modified to some extent without. departing materially from the essential features of the invention. It is my intention,

therefore, to include all'such modifications within the scope of the appended claims.

What is claimed is:

1 In an excavating machine, the combination of a boom mounted to move .upwardly and downwardly, a member pivotal- -ly connected to the outer end of the boom, ascoop carried by said memberpa" hoisting line, means connecting the hoisting line to the scoop carrying member at a point above .3:

nation of a boom mounted to move upwardly and downwardly, a ditcher stick intermediately pivoted to the outer end of the boom,

a hoisting line, means pivoted to the stick above its pivot for connecting the hoisting line therewith, and means dependent upon the operation of the boom for temporarily suspending the action of the pivot at the upper end of the stick during acertain part J1 of the cycle of operation. v. I

3. In an excavating machine, the. combinationof a boom mounted to move upwardly and'downwardly, a ditcher stick intermediately pivoted to the outer end of the boom,

a connecting member pivoted to the stick above the pivotal connection of the latter with the boom, a hoist lineattached to the connectin member, and means for limiting the 'angu ar approach of the stick to said connecting member. g 4. In an excavating machine, the combination of a boom pivoted to move upwardl and downwardly, a ditcher stick intermeiiiately pivoted to the outer end of the boom, a member pivotally connected to the upper end of the stick, a hoisting lme connected' to said link member, and means for tem orarily fixing said link member at a predetermined angle .with relatlon to the stick during a certain part of the cycle or the link member and extending inwardly therefrom, said link member being normally free to move about its plvot and to normally remain in a position of alinement with the direction of tension in the hoisting line, and

means for causing the inward movement 0t,

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the lower end of the stick to be opposed, (luring. a part of the operating cycle, by the tendency of said link member to remain in alinement with the direction of tension in the hoisting line.

y 6, In an excavating machine, the combination of a boom pivoted to move upwardly and downwardly, a ditcher stick pivotally supported at the outer end of the boom, a scoop secured to the lower end of said stick, a connecting bar pivoted to the stick above the pivotal connection between the latter and the boom, a hoisting line connected to said bar, and inter-engageable abutments on the connecting bar and ditcher stick respectively, limiting their relative approach toward each other.

7. In an excavating machine, the combination of a boom pivoted to move upwardly and downwardly, a ditcher stick pivotally supported intermediate its ends by the outer end of the boom, a scoop secured to the lower end of said stick, a connecting bar pivoted to the upper end of the stick, a hoisting line connected to said bar, a hauling line connected to the scoop, an abutment secured to and extending downwardly from the connecting bar, and an abutment secured in rigid relation to said stick and extending inwardly and upwardly therefrom toward the, bar and engageable by the first mentioned abutment to limit the relative angular approach of the connecting bar toward the ditcher stick.

8. In an excavating machine, the combination of a boom pivoted to move upwardly and downwardly, a ditcher stick pivotally connected intermediate its ends to the outer end ofthe boom,'a scoop secured to the 7 lower end of said stick, a hoisting line connected to said stick, a hauling line connected to the scoop, and an abutment secured to the under side of the connecting bar and engageable with a part carried by the boom to oppose downward movement of said ,con necting bar about its pivot.

9. In an excavating machine, the combination of a boom pivotally mounted to move upwardly and downwardly, a ditcher stick intermediately pivoted to the outer end of the boom, a link member pivotally connected at one end to the upper end of the stick, a hoisting line connected to the other end of the link member and extending inwardly therefrom, said link member being normally free to move about its pivot and to remain in a position of alinement with the direction of tension in the hoisting line, and means for deflecting the link member out of alinement with the direction of tension of the hoisting line whenever the boom and stick and direction of tension of the hoisting line come into such a relationship that, except for said deflecting means, the direction of tension of the hoisting line would pass ap roximately through the pivotal connection between the boom and the stick.

10. In an excavating machine, the combination of a boom-mounted to move upwardly and downwardly, a ditcher stick pivotally connected to the outer end of the boom, a scoop carried by said ditcher stick, a hoisting line, means connecting the hoisting line to the ditcher stick at a point above the pivotal connection of the latter to the boom, and means for deflecting upwardly the direction of the pull exerted by the hoisting line u on the ditcher stick whenever the line 0 pull would otherwise pass approximately through the pivotal connection between the boom and the stick.

In testimony, that I claim the foregoing as rmy own, 1 have hereto affixed my signature,

ROBERT REX DOWNIE. 

